The present invention is an improvement on the general vehicle structures forming the subject matters of U.S. Pat. Nos. 4,157,739 and 4,357,893 to Frye, in each of which the basic disclosure is a two-wheel, all-terrain vehicle in which both front and rear wheels are powered, as by hydrostatic motors, and simultaneously steered in opposite directions in order to decrease the steering radius. One disadvantage of a vehicle of that type is that the wheels are fork mounted, as in typical bicycles or motorcycles, and, when the vehicle is used in rough, muddy, etc. terrain, the forks accumulate various forms of debris, mainly mud and mud-packed stones and the like, which obviously interferes with efficient operation of the vehicle.
According to the present invention a steerable wheel structure is provided which does not require a steering fork. Instead, the wheel is disposed between opposite side supports of the vehicle and has transverse axle means including opposite ends connected to fore-and-aft, right and left force-exerting means. The connections of the axle ends to the force-exerting means includes provision for articulation, especially about right and left upright pivots about which the wheel is selectively turned as distinguished from a central axis as in a fork-mounted wheel. In addition to the flexibility and other advantages accruing from such an arrangement, the structure profits from stability and rigidity derived from the side wall or support structure. The steering arrangement is further such that the wheel moves bodily laterally, for example, away from the left wall on right turns and vice versa, thus increasing the amount of turning space available without interference between the wheel and side wall. Other features and advances flow from the guide means provided to assure efficient operation with a minimum of maintenance and repair.
These and other features and advantages will become apparent as the invention is disclosed in detail in the ensuing description and accompanying sheets of drawings.